The present invention relates to a maintenance stem for a card reader for performing various card processes such as a card convey process for conveying an inserted card and a process for recording/reproducing value information on/from the conveyed card.
In a vending machine for vending various articles using a prepaid card (to be referred to as a card hereinafter) on which prepaid value information is recorded, a card reader for reproducing the value information recorded on the card and recording remaining value information is arranged. When a card is inserted into such a card reader, the card is conveyed to the position of a recording/reproducing head in a card convey path by the rotation of a motor, the value information recorded on the card is read out, and the read value information of the card is displayed. In this case, when a user operates an article selection button of the vending machine to buy an article, the corresponding article is vended. At this time, in the card reader, value information corresponding to the amount of the vended article is subtracted from the read and displayed value information, remaining value information is written in the card by the recording/reproducing head, and then the card is conveyed in the card convey path and returned to a card return port.
In this card reader, each time a card is used, the above various card processes constituted by the card convey process and the process for writing/reading value information in/from the card are performed. If the card reader is broken, the broken card reader is returned to a factory so as to be repaired. However, in this case, since the card reader having an unknown broken portion is often returned to the factory, a cumbersome process must be performed to recognize the broken portion. As a result, a long time is required to repair the broken card reader.